Fifth wheel

ABSTRACT

A fifth wheel is described with a coupling plate having elements for fastening to the vehicle frame. It is supposed to facilitate the mounting on the vehicle frame, while it should be possible to equalize manufacturing tolerances of the frame in simple fashion. The fastening elements attach to pivot pins, which are detachably arranged on the fifth wheel and project outward to the side beyond the coupling plate.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit of PCT Application No. PCT/EP98/03916filed Jun. 26, 1998 and German Application No. 19727338.6 filed Jun. 27,1997.

BACKGROUND OF THE INVENTION

The invention concerns a fifth wheel for a truck, with a coupling plateand with means to fasten the fifth wheel to the vehicle frame in theform of two pivot pins, which are fashioned at the side at twodiametrically opposite places underneath the top of the coupling plateon the fifth wheel and which project out to the side beyond the couplingplate, and which have a bearing segment and a fastening segment.

Fifth wheels are mounted in bearing pedestals, which are either anintegral part of the vehicle frame or are screwed onto the vehicle frameand can swivel about a horizontal axis. The bearing pedestal isconnected to the fifth wheel by bolts, which are inserted into thebearing pedestal and corresponding openings of the coupling plate.Bearing pedestals which are fastened on the vehicle frame or which areintegral parts of the vehicle frame are known, for example, from EP 0087 903 B1 and DE 43 22 717 A1. These bearing pedestals have a bearingtube, through which the bearing bolts can be inserted.

Moreover, there are fifth wheels that have pockets with inserted rubberbearings underneath the coupling plate. Here as well the fastening tothe bearing pedestals is done by bearing pins, which are inserted intothe side walls of the pockets and through the bearing pedestal. Sucharrangements are known from DE-PS 23 03 163, DE 30 40 925 C2, EP 0 038928, EP 0 114 046 and DE-PS 14 30 462.

All solutions have the common drawback that the fifth wheel duringassembly must be oriented exactly to the frame and, thus, to theopenings of the bearing pedestals before the bearing bolts can beinserted. This requires considerable assembly expense. A furtherdisadvantage results from the manufacturing tolerances of the vehicleframe. The frame pieces and, thus, the spacing of the bearing pedestalscan be of different size, so that a stable fastening of the fifth wheelcannot always be achieved without resorting to additional steps.

The drawbacks of these known designs with inserted bearing bolts orbearing pins are avoided by the above-mentioned fifth wheel with thepivot pins arranged on both sides directly on the fifth wheel, having abearing segment and a fastening segment. The bearing segment is thatpart of the pivot pin which lies in the bearing pedestal. The fasteningsegment, instead, is responsible for mounting on the fifth wheel.

This design has become known, for example, through DE 28 36 703 A 1 andU.S. Pat. No. 3,198,548.

Through this known design, the assembly is significantly facilitatedand, thus, the assembly time is shortened. The fifth wheel is loweredfrom above onto the vehicle frame, the pivot pins engaging with recessesof the bearing pedestal, arranged on the vehicle frame. The fifth wheeladjusts itself, without requiring additional measures. After this, thepivot pins are secured to the bearing pedestal by means of acorresponding fastening means, which shall be discussed hereafter inconnection with the bearing pedestal.

Furthermore, manufacturing tolerances of the vehicle frame can beequalized. The pivot pins can be made to excess length, so that evenwhen the frame spacing is too large a secure fastening on the bearingpedestal of the vehicle frame can be assured. If, at normal framespacing, the pivot pins then project slightly to the outside from thebearing pedestal, this is acceptable.

In such a mounting of the fifth wheel, the fastening of the two pivotpins to the coupling plate becomes especially important, since they mustconvey the forces emanating from the fifth wheel plate during operationand diverted into the vehicle frame.

In the known fifth wheels, therefore, the pivot pins are joined to thefifth wheel as a single piece (material closure), in particular, welded,as specifically stated in the U.S. patent.

This type of fastening has the major disadvantage that, for applicationswhich require different bearing bolts for the same fifth wheel plate,entire fifth wheel plates must be kept on hand with the correspondingbearing bolts each time. This circumstance increases the logisticalexpense, in particular, inventory is more costly, and it also prevents amodular system.

SUMMARY OF THE INVENTION

The basic purpose of the invention is to configure the above-indicatedfifth wheel such that the fifth wheel can be adapted to differentapplications in a simple yet safe manner.

This purpose is accomplished, according to the invention, in that eachpivot pin is detachably fastened to the fifth wheel in at least twoplaces.

The detachably secured pivot pins have the advantage that the fifthwheel can be adapted by simple replacement of the pivot pins todifferent installation circumstances, such as different frame spacings,while using the same coupling plate each time.

The secure fastening of the pivot pin with respect to the forcesoccurring is assured in that the pivot pin is fastened to at least twoplaces on the fifth wheel. Preferably, according to a furtherdevelopment of the invention, the fastening segment is screwed to thefifth wheel at its front end and additionally held in the fifth wheel atits end near the bearing segment.

In order to achieve a deep installation position of the fifth wheel,according to one configuration of the invention the fastening segmentand the bearing segment of the pivot pin can be offset from each other.This also opens up the possibility of securing the fastening segment atthe point of the fifth wheel where an appropriate stability exists.

The pivot pin can have a cylindrical shape. Other configurations arealso possible, but one must adapt to the particular bearing pedestals.

Preferably, the pivot pin carries a bushing, which can consist of aplastic material having especially good sliding properties. Preferably,bushing material and pivot material are attuned to each other in respectof a good slide fitting.

According to another embodiment, the bushing can carry a rubber inserton its outside, which creates an elastic mounting. When fastening thepivot pin, the rubber insert is compressed, producing tension on thepivot pin. It is also possible to equalize manufacturing tolerances withthis design. The bushing with the rubber insert can also be preassembledon the pivot pin.

The pivot pin can also carry a spherical or ball-shaped extruded part,which interacts with a corresponding mate in the bearing.

According to another embodiment, the pivot pin can have a round endsurface, which has the advantage that no additional extruded part isneeded, since the pivot pin is salient with respect to the counterpartof the bearing.

Moreover, the ball-shaped bearing is well suited to compensate fortwisting of the vehicle frame.

The bearing pedestal mounted on the vehicle frame and intended toaccommodate the fifth wheel according to the invention is characterizedin that it has a bottom piece with a recess on top and at least oneholding element detachably secured to the bottom piece. The recess ispreferably adapted to the shape of the pivot pin of the fifth wheel, sothat a swivel bearing is achieved. Therefore, the recess is preferablysemicircular in shape.

The recess can also have a different configuration, if, for example, thepivot pin of the fifth wheel is enclosed in an elastic material, whichallows a limited swinging of the fifth wheel.

The holding element for fastening the pivot pin can be a half-clip,which is placed on the pivot pin and secured to the lower piece of thebearing pedestal after the fifth wheel is mounted.

According to another embodiment, the holding element can be a bearingcap embracing the pivot pin, which is secured to the bearing pedestalduring assembly. The bearing cap preferably has an inner contour adaptedto the shape of the pivot pin. The outer contour of the bearing cap isadapted to the recess of the bearing pedestal, so that a form-fittingconnection to the bearing pedestal can be created.

The bearing cap, which likewise can be preassembled, can carry a bushingwith a spherical or ball-shaped surface, which interacts with thespherical or ball-shaped extruded part of the pivot.

Sample embodiments of the invention shall be explained more closelyhereafter by means of the drawings.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1, a top view of a fifth wheel mounted on the vehicle frame,

FIG. 2, a section along line II—II of the layout in FIG. 1,

FIG. 3, a side view of a bearing pedestal,

FIG. 4, the top view of a fifth wheel, partly in cross section,according to another embodiment,

FIG. 5, a side view of a bearing pedestal according to anotherembodiment,

FIG. 6, a vertical section through a bearing pedestal according toanother embodiment,

FIG. 7, a top view of a fifth wheel according to another embodiment, and

FIG. 8, the side view of a pivot pin.

DETAIL DESCRIPTION OF THE INVENTION

FIG. 1 shows a fifth wheel 3 in top view, of which basically thecoupling plate 10 is seen. At the opposite side surfaces 11 a and 11 b,outwardly projecting pivot pins 12 a,b are detachably mounted, beingcylindrical in shape in the embodiment shown here. The pivot pins 12 a,blie on bearing pedestals 30 a,b, which are mounted on longitudinal beams2 a,b of a vehicle frame 1. The bearing pedestals 30 a,b each have arecess 34 in their bottom piece 31, in which the pivot pin 12 a,bengages when assembled (see FIG. 3). The pivot pins 12 a,b are securedaccording to the embodiment shown in FIG. 3 by means of a half-clip 32a,b, which forms the top of the bearing pedestal 30 a,b. By means ofscrews 33, the half-clip 32 a,b is fastened to the bottom piece 31 ofthe bearing pedestal 30 a,b.

As can be seen in FIG. 1, the length of the pivot pins 12 a,b is adaptedto the width of the longitudinal beams 2 a,b and, thus, to the length ofthe recesses 34 of the bearing pedestal. In the depiction of FIG. 1, thepivot pins 12 a,b project slightly outward by their end faces 13 a,bfrom the outside of the bearing pedestal 30 a,b. Manufacturingtolerances, such as different spacings of the longitudinal beams 2 a,b,are equalized by the pivot pins 12 a,b in that these might not lieacross the entire length of the recesses 34 a,b. On the other hand, itcan be possible to configure the pivot pins 12 a,b longer than thebearing pedestals are broad or their recesses 34 are long. In this case,the pivot pins 12 a,b would project noticeably outward from the bearingpedestals 30 a,b.

FIG. 2 shows a cross section along line II—II of the arrangement in FIG.1. It can be clearly seen that the bearing pedestals 30 a,b are arrangedonly slightly beneath the top 46 of the coupling plate 10. This achievesa deep installation position of the fifth wheel 3.

In FIGS. 1-3, it can be seen that the pivot pins 12 a,b carry bushings40 a,b, which can be fashioned as bearing bushings. Preferably, aplastic material is used that has good sliding properties with respectto the pin material, so that the fifth wheel 3 can swing about thehorizontal axis 60. FIG. 4 shows another embodiment of a fifth wheel 3,which likewise has detachably secured pivot pins 12 a,b, in which thefastening is visible thanks to the partly exploded view. The pivot pins12 a,b have a bearing segment 16 a,b, which rests on the bearingpedestal 30 a,b and carries the bushing 40 a,b. In the embodiment shownhere, the bushings 40 a,b additionally have rubber inserts 43 a,b ontheir outside, which project slightly radially outward from the surfaceof the bushing 40 a,b. These rubber inserts are compressed duringinstallation, so that the bearing bushing 40 a,b in which the pivot pins12 a,b is immovably secured.

The fastening segment 15 a,b protrudes into the fifth wheel 3. The frame4 of the coupling plate 10 has an opening 6 a,b in its outer wall 5 a,b,through which the pivot pin 12 a,b extends. This opening 6 a,b has ashoulder 7 a,b, against which rests a flange 18 a,b formed on the pivotpin 12 a,b. The fastening segment (15 a,b) is greater than or equal to aprotruding length of the bearing segment (16 a,b).

The rear end face 14 is fastened by means of screws 19 to a web 8 a,b ofthe frame 4. The bearing bolts 12 a,b are thus secured to the fifthwheel at two fastening points, so that the forces acting on the fifthwheel 3 can be channeled into the bearing pedestals 30 a,b , without thepivot pins 12 a,b becoming noticeably deformed, even in extremesituations.

FIG. 5 shows the side view of a bearing pedestal 30, whose bottom piece31 has a semicircular recess 34. The top of the bearing pedestal 30 a,bis formed by a bearing cap 35 a,b, whose outer contour is adapted to theshape of the recess 34. The bearing cap 35 a,b embraces the pivot pin 12a,b and thus can be preassembled. The bearing cap 35 a,b is secured bymeans of screws 37 on the bottom piece 31 of the bearing pedestal 30a,b. The pivot pins 12 a,b and the bushings 40 a,b with the inserts 43a,b are drawn hatched in FIG. 5.

FIG. 6 shows a cross section through a bearing pedestal 30 a,b accordingto another embodiment. The pivot pin 12 b, which has a cylindrical outercontour, carries an extruded part 45, which has a spherical surface 47.In the bearing cap 35 is placed a bushing 41, which likewise has acorresponding spherical inner surface 42, being adapted to the sphericalsurface 47. Manufacturing tolerances in the axial direction (in thedirection of the swivel axis 60) can be easily compensated in this way.It should be noted that the bearing bolt 12 b does not rest with its endsurface 13 b against the front wall 36 of the bearing cap 35.

FIG. 7 shows another embodiment in which the pivot pins 22 a,b have acircular cross section, tapering in the direction of the coupling plate10. The end face 23 a,b is rounded off, so that the pivot pin 22 a,b hasa generally drop-shaped form. Inside the bearing cap 35 there is placeda bearing insert 44 a,b of elastic material, embracing the pivot pins 22a,b.

FIG. 8 shows an embodiment of a replaceable pivot pin 12 a, in which thefastening segment 15 a and the bearing segment 16 a are offset from eachother. The connection is produced by a middle segment 50. Thisembodiment is suitable for applications in which the fifth wheel issupposed to be arranged as deep as possible in the vehicle frame 1.

LEGEND

1 Vehicle frame 2a,b Longitudinal beam 3 Fifth wheel 4 Frame 5a,b Outerrim 6a,b Opening 7a,b Shoulder 8a,b Web 10 Coupling plate 11a,b Sidesurface 12a,b Pivot pin 13a,b Front end face 14 Rear end face 15a,bFastening segment 16a,b Bearing segment 18a,b Flange 19 Screws 22a,bPivot pin 23a,b End face 30a,b Bearing pedestal 31 Bottom piece 32a,bHalf-clip 33 Screw 34 Recess 35a,b Bearing cap 36 Front wall 37 Screw40a,b Bushing 41 Bushing 42 Spherical surface 43a,b Insert 44a,b Bearinginsert 45 Extruded part 46 Top 47 Spherical surface 50 Middle segment 60Horizontal axis

What is claimed is:
 1. A fifth wheel for mounting to a vehicle framecomprising; a coupling plate; two pivot pins detachably connected tosaid plate at two diametrically opposite points at sides of saidcoupling plate said pins projecting out to the side beyond the couplingplate, said pins having a bearing segment and a fastening segment, eachsaid pivot pin being detachably fastened to at least two points to saidcoupling plate wherein the fastening segment is fastened at a free endface of a said pivot pin to the coupling plate and additionally held bythe coupling plate at an end near the bearing segment; and at least onepair of bearing pedestals, said bearing pedestals adapted to be mountedto the frame of a vehicle, each of said pivot pins operably connected toa said separate bearing pedestal.
 2. A fifth wheel according to claim 1,wherein the fastening segment is screwed at a free end face to saidcoupling plate and is additionally held by said coupling plate at an endnear the bearing segment.
 3. A fifth wheel according to claim 1, whereinthe fastening segment having a protruding length that is greater than orequal to in length than a length of the bearing segment of said pivotpin.
 4. A fifth wheel according to claim 1, wherein the fasteningsegment and the bearing segment of the pivot pin are arranged at anoffset.
 5. A fifth wheel according to claim 4, wherein the pivot pinshave a cylindrical shape.
 6. A fifth wheel according to claim 1, whereinthe pivot pins carry a bushing.
 7. A fifth wheel according to claim 1,wherein the pivot pins carry an extruded part, which has a spherical orball-shaped surface.
 8. A fifth wheel according to claim 1, wherein thepivot pins have a round end face.
 9. A fifth wheel according to claim 1,wherein said pair of bearing pedestals accommodates a respective pivotpin of the fifth wheel, said at least one of said pair of bearingpedestals having a bottom piece with a recess located on a top sidethereof, and at least one holding element detachably secured to thebottom piece.
 10. A fifth wheel according to claim 9, wherein the recessis semicircular.
 11. A fifth wheel according to claim 9, wherein theholding element is a half-clip.
 12. A fifth wheel according to claim 9,wherein the holding element is a bearing cap embracing the pivot pin.13. A fifth wheel according to claim 12, wherein an inner contour of thebearing cap is adapted to a shape of the pivot pin and an outer contourto a shape of the recess.
 14. A fifth wheel according to claim 12,wherein the bearing cap comprises an inserted bushing with a sphericalor ball surface.
 15. A fifth wheel assembly for a vehicle framecomprising: a coupling plate; at least one pivot pin, said at least onepivot pin having a bearing segment and a fastening segment and, said atleast one pivot pin detachably fastened through said fastening segmentto said coupling plate; and at least one bearing pedestal, said at leastone bearing pedestal adapted to be mounted to the frame of a vehicle,and said at least one pivot pin operably connected through said bearingsegment to said at least one bearing pedestal.
 16. A fifth wheelassembly according to claim 15, wherein said fastening segment and saidbearing segment of said pivot pin of arranged at an offset.
 17. A fifthwheel assembly according to claim 16, wherein said assembly furthercomprises a bushing or extruded part, said bushing or extruded partoperably connected to said pivot pin.